Wei C J, Cheng C Y
Department of Chemical Engineering, National Central University, Chung-Li, Taiwan 320, Republic of China.
Biotechnol Bioeng. 1985 Oct;27(10):1418-26. doi: 10.1002/bit.260271005.
Assessment was made to evaluate the effect of hydrogen peroxide pretreatment on the change of the structural features and the enzymatic hydrolysis of rice straw. Changes in the lignin content, weight loss, accessibility for Cadoxen, water holding capacity, and crystallinity of straw were measured during pretreatment to express the modification of the lignocellulosic structure of straw. The rates and the extents of enzymatic hydrolysis, cellulase adsorption, and cellobiose accumulation in the initial stage of hydrolysis were determined to study the pretreatment effect on hydrolysis. Pretreatment at 60 degrees C for 5 h in a solution with 1% (w/w) H(2)O(2) and NaOH resulted in 60% delignification, 40% weight loss, a fivefold increase in the accessibility for Cadoxen, an one times increase in the water-holding capacity, and only a slight decrease in crystallinity as compared with that of the untreated straw. Improvement on the pretreatment effect could be made by increasing the initial alkalinity and the pretreatment temperature of hydrogen peroxide solution. A saturated improvement on the structural features was found when the weight ratio of hydrogen peroxide to straw was above 0.25 g H(2)O(2)/g straw in an alkaline H(2)O(2) solution with 1% (w/w) NaOH at 32 degrees C. The initial rates and extents of hydrolysis, cellulase adsorption, and cellobiose accumulation in hydrolysis were enhanced in accordance with the improved structural features of straw pretreated. A four times increase in the extent of the enzymatic hydrolysis of straw for 24 h was attributed to the alkaline hydrogen peroxide pretreatment.
进行评估以评价过氧化氢预处理对稻草结构特征变化和酶解的影响。在预处理过程中，测定了稻草的木质素含量、失重、对卡多克森试剂的可及性、持水能力和结晶度的变化，以表征稻草木质纤维素结构的改性情况。测定了水解初始阶段的酶解速率和程度、纤维素酶吸附量以及纤维二糖积累量，以研究预处理对水解的影响。在含有1%（w/w）H₂O₂和NaOH的溶液中于60℃预处理5小时，与未处理的稻草相比，导致60%的脱木质素率、40%的失重、对卡多克森试剂的可及性增加五倍、持水能力增加一倍，且结晶度仅略有下降。通过提高过氧化氢溶液的初始碱度和预处理温度，可以改善预处理效果。在32℃下，在含有1%（w/w）NaOH的碱性H₂O₂溶液中，当过氧化氢与稻草的重量比高于0.25 g H₂O₂/g稻草时，发现稻草结构特征得到了充分改善。随着预处理稻草结构特征的改善，水解初始阶段的酶解速率和程度、纤维素酶吸附量以及纤维二糖积累量均有所提高。稻草24小时酶解程度提高四倍归因于碱性过氧化氢预处理。
